In computer and other applications, it is commonly necessary to form a plurality of electrical connections between two printed circuit boards. These connections can be achieved through an interface between an edge of one printed circuit board and an electrical connector mounted on the other printed circuit board. Each application requires a certain orientation of the boards relative to each other. For example, the application may require that the boards be positioned perpendicular to each other. Other applications may require the boards to be positioned parallel to each other. One way to achieve a parallel interface is to mount a right angle electrical connector on a printed circuit board which receives the edge of the other board.
One such example is shown in U.S. Pat. No. 5,219,295. That patent teaches a high density electrical connector having a housing with contacts arranged in rows to engage a printed circuit board. The housing supports the contacts in a right angle orientation. Another example of such a right angle connection is shown in U.S. Pat. No. 5,533,901. That patent teaches an electrical connector having a housing which supports multiple electrical contacts each having terminals which are profiled to be mounted to a printed circuit board at a right angle.
As microprocessor clock speeds and signal speeds continue to rise there is an ever increasing need for better signal isolation in small electrical connectors. This is typically achieved by use of a ground plane adjacent to the signal contacts in the connector.
In some interconnection arrangements such as the arrangements described above a problem exists in the it is often difficult to have the ground plane extend over the entire length of the signal contacts. This is desirable because it minimizes the signal to ground distance and therefore gives better signal isolation. Depending on the signal speed of each application, different ratios of signal to ground contacts are desirable to achieve proper isolation and acceptable electrical performance. A problem exists with current designs in that once a connector is manufactured with a specified signal to ground contact ratio, that ratio can not be changed without redesigning the housing, contacts and ground plane.
It is therefore desirable to have a connection system design that would allow flexibility in creating different signal to ground contact ratios.